The present invention relates to clamps for preventing the flow of fluids through bodily vessels and, more particularly, to an atraumatic clamp for occluding blood vessels during surgery.
Typical prior art vessel occluding devices are designed in "O", "J" or "C" shapes with vessel contacting surfaces on their inner aspects which completely surround the vessel. When occluding pressure is applied to the vessel (such as by inflation of one or more balloons within the device in contact with the vessel), the vessel is compressed by a constricting force applied around its entire circumference. Some examples of these types of prior art devices are described below.
It has been observed that significant trauma to the vessel often results from the use of such prior art occluding devices. Applicant has discovered that the cause of this trauma is attributed to the design of these devices and the way in which they apply compressive forces to the vessel. Specifically, the radially directed compressive forces applied completely around the circumference of the vessel preclude lateral extension of the vessel, thus forcing the vessel tissue to compress longitudinally--a direction in which it has relatively little compliance. The high compressive forces required to effect this longitudinal compression and occlusion of the lumen of the vessel result in an actual crushing of the vessel tissue, with consequent damage. The trauma is aggravated in the case of diseased vessels, such as those suffering from the effects of arteriosclerosis. The thickened and hardened vessel wall exhibits less than the normal degree of compliance upon compression, and the encircling compressive forces of the prior art clamps do not accommodate localized excessive thickening.
U.S. Pat. No. 4,399,809 to Baro et al. discloses an artificial sphincter designed to be wrapped around an intestine or other anatomical vessel. One embodiment of the artificial sphincter comprises a flexible strip having attached thereto a plurality of inflatable chambers interconnected by tubing. A gas supply tube is also provided to one of the chambers. When the strip is wrapped around the vessel, the strip and inflatable chambers form a circular (i.e., O-shaped) clamp having four simultaneously inflatable chambers, each of the chambers exerting pressure when inflated on one quadrant of the vessel. Unfortunately, this circular type of clamp, which applies pressure to the entire circumference of the vessel, is unable to provide sufficient compressive force to occlude the vessel's inner lumen without damaging the vessel.
Similarly, "C" and "J" balloon clamps having one or more inflatable balloons along the inner aspect of the curved portions of C-shaped or J-shaped frames suffer from the same disadvantages, namely, an undesirable degree of trauma imparted to the vessel in order to achieve complete occlusion of the inner lumen.
U.S. Pat. No. 4,222,377 to Burton discloses a circular artificial sphincter having three inflatable balloons positioned along and completely covering the inner aspect of an O-shaped frame. Although the Burton device is specifically designed as an artificial sphincter for treating incontinence, because of its design it too can impart an undesirable degree of trauma to the vessels which it is designed to occlude.
U.S. Pat. No. 4,408,597 to Tenney, Jr. discloses a circular clamp for occluding the lumen of an internal organ. The clamp comprises a circular (i.e., O-shaped) frame having two inflatable balloons positioned along the inner aspect. One of the two balloons is always inflated while the second balloon may be inflated or deflated in order to control the degree of occluding presure applied to the vessel. Accordingly, the two balloons are not simultaneously inflatable. Even though only two balloons are provided, this type of clamp also can impart significant traumatic damage to the vessel due to the fact that the two balloons engage substantially the entire circumference of the O-shaped frame.
U.S. Pat. No. 4,404,971 to LeVeen et al. discloses a completely different type of device for occluding the flow of fluid through a bodily vessel. The LeVeen device comprises a hollow catheter having two inflatable balloons disposed along the length of the catheter, spaced apart from one another. The catheter and the balloons (in a deflated condition) are threaded into the interior of the vessel. Once the catheter and balloons are positioned completely within the vessel, air is pumped through the catheter in order to inflate the balloons. The balloons expand within the interior of the vessel until contact is made around the entire inner circumference of the vessel wall. Accordingly, each of the balloons acts to independently stop fluid flow through the vessel. Drawbacks to the use of this type of device include the need for a surgical incision in the vessel itself, and difficulties involved with threading and positioning the catheter and balloons in the vessel.